Techno-Economic Analysis of an Improved Process for Producing Saturated Branched-Chain Fatty Acids

Methyl-branched fatty acids produced by isomerization of oleic acid (‘isostearic’ acids (IA)) are industrially useful products with excellent thermostabilities and lubricities and reduced freezing points relative to stearic acid. They have potential utility as biodiesel or a biodiesel additive imparting improved low temperature fluidity. We present a techno-economic model for industrial scale production of isostearic acid by zeolite-catalyzed isomerization. A catalyst regeneration loop allowing 20 reaction cycles was included. Use of catalyst for 15 or more reaction cycles reduced process cost by 51% vs. a single use reaction format. However, with a best-case predicted production cost of $2.375/kg ($1.080/lb), further process cost reductions will be required before use of IA esters as high percentage blend components of biodiesel is economically feasible.